Katsuki Bakugo grew up in the same neighborhood as Izuku Midoriya since they were young children. Izuku and Katsuki's other childhood friends have him the nickname "Kacchan". Izuku and the other boys always looked up to Katsuki because of his energy, confidence and natural born talent. Katsuki often picked on Izuku and gave him the nickname "Deku".
Katsuki always admired All Might when he was young because the number one hero would always win against the odds. While watching a video of him at the electronics store, Katsuki tells his friends that All Might is the greatest hero because of his ability to achieve victory. Sometime later, Katsuki defeated a few fourth graders who bumped into him. With Izuku looking on, Katsuki says that the most amazing hero always wins no matter what. 
Once Katsuki developed his Quirk Explosion, his aggressive tendencies transformed into heinous bullying. He was constantly praised for his powerful Quirk and developed a twisted superiority complex as a young child. Believing himself to be better then everyone else, Katsuki looked down on Izuku especially because he lacked a Quirk all together.
Izuku still considered the two friends at the time, but things escalated when Izuku tried to help Katsuki after he fell off a small bridge into a stream. Izuku offered a helping hand, but Katsuki took this an insult. He believed that Izuku made him appear as if he needed aid from someone who is beneath him. This would strain the relationship between the two for years to come.
During class at Orudera Junior Highschool, the teacher announces that all students will graduate, and Katsuki contends the notion that he is of the same status as his peers. He refers to his classmates as beneath him and tells them all that he alone will attend U.A. High and surpass the number one hero: All Might.
His teacher discloses that Izuku is also attempting to get into U.A., much to Katsuki's displeasure. He berates Izuku and uses his Quirk to scare him. He tells Izuku that because he is Quirkless, he will never succeed at anything, especially getting into U.A.
Katsuki and two of his friends confront Izuku after class. They take take his hero notebook and Katsuki burns it before tossing it out the window into a fish pond. Katsuki reminds Izuku that only he himself is destined to reach that school and Izuku is just a stepping stone for his greatness. Before leaving, Katsuki warns Izuku not to apply to U.A. at all.
After school, Katsuki and company try to decide what to do for fun and ponder if Katsuki was too harsh on Izuku. Katsuki ignores them, only replying that he cannot stand Izuku's optimism and someone needs to teach him how the world works. Just then, the Sludge Villain captures Katsuki and goes on a rampage through the city. Katsuki tries to break free using his Quirk, but is unable to, only setting fire to the area around him and making it more difficult for heroes to intervene.
As people and Heroes are watching, unable to help Katsuki, Izuku rushes to help him. While Katsuki demands to know why Izuku's helping him, Izuku states that he could not stand by and let Katsuki die. The two are ultimately saved by All Might, who destroys the villain while freeing Katsuki at the same time. Afterwards Izuku is scolded for his recklessness and Katsuki is praised for his Quirk, but the latter only frowns in silence. Later, he finds Izuku and yells at him for trying to help. Katsuki claims he was fine on his own and never needed any help before angrily storming away.
Months later, Katsuki arrives to take part in the U.A. Entrance Exam. While walking in, Katsuki notices Izuku walking in and tells him to move out of the way. Later in the auditorium, Katsuki is seated next to Izuku, whom he has to tell to shut up after he starts geeking out over Present Mic being the examiner. Katsuki is also upset by the fact that he and Izuku must participate in separate areas because Katsuki was excited to crush him.
After the exam begins, judges note that Katsuki took on the exam using brute force and combat ability. By the test's end, Katsuki scored seventy-seven combat points, the most out of any participant. He also received the lowest amount of rescue points, and was the only student not to get any rescue points at all. Examiners were still impressed by his performance. They make note of how he remained calm after the zero pointer arrived, and took out the smaller bots with ease.
At the end of Orudera's academic year, Katsuki and Izuku are praised by their teacher for being the only two students in school history to get accepted into U.A. Katsuki angrily demands to know what trick Izuku used to pass the exam. Katsuki wanted to be the only one from their school to attend U.A. and threatens for Izuku to change schools. However, Izuku stands up to Katsuki for the first time and refuses, claiming that he now has someone who believes in him and he won't let them down.
April arrives and the U.A. academic year begins. On the very first day, Katsuki is argues with Tenya Iida about having his feet on the desk. Iida tries to introduce himself calmly, but Katsuki recognizes him as just another stepping stone and threatens to crush him. Their teacher, Shota Aizawa arrives and takes them out to the P.E. field for a quirk assessment test. Mister Aizawa uses Katsuki as an example to explain the test. Throughout middle school, physical tests were always given without quirks in mind. This lead to Katsuki only throwing about sixty-five meters on his original ball toss. This time, Katsuki uses his Quirk to throw the ball and his explosive toss sends the ball over seven hundred meters.
The class goes through several different physical tests, including a fifty meter dash and a standing long jump. Katsuki uses his quirk to excel in both and claims that his quirk is the most versatile in the class. When Izuku takes the pitching test, Katsuki mocks him but is shocked when Izuku uses a Quirk to toss the ball as far as he did. Katsuki questions why Izuku never got his Quirk as a kid and angrily tries to attack Izuku for an explanation, but Shota stops him from doing so using his Quirk and capture weapon.
The next day at school during Hero Basic Training, Katsuki and the other students suit up in their hero costumes for combat training. Katsuki is teamed with Tenya Iida on Team D and must face off with Team A, consisting of Izuku and Ochaco Uraraka. Team D are assigned the villainous mission protect a warhead inside a building. Team A is assigned the task of stopping the villains by capturing the payload or the villains themselves.
As combat training begins, Katsuki still ponders over Izuku's Quirk. He goes off his own and attempts to ambush Izuku, but is countered twice thanks to notes taken by Izuku. Izuku reveals that the same notebook Katsuki burned and threw out had notes about Katsuki's moves. Finally standing up to Katsuki, Izuku tells him that he is no longer the same kid Katsuki used to bully and the name Deku would be a hero name. Then Izuku retreats, forcing Katsuki to search the building alone, giving Uraraka a chance to escape and find Tenya. Tenya tries to contact Katsuki, but he is too focused on fighting Izuku and ignores him.
Katsuki eventually finds Izuku, demanding he use his quirk while revealing information about his own. Katsuki's Explosion Quirk works by detonating the nitroglycerin he sweats. The gauntlets on his costume store this "nitro-sweat", and once full Katsuki can fire off a huge blast.
All Might cautions him not to use the attack, but Katsuki does so anyway. Izuku narrowly evades and the blast destroys a large portion of the building. All Might warns Katsuki should he use that attack again, his team will be disqualified.
Katsuki takes the duel into close quarters, where he easily dominates Izuku. He uses his explosions to change trajectory in the air and blast Izuku from behind. Then he grabs onto Izuku's arm and slams him into the ground after using explosions from his free hand to build up momentum. Katsuki's fighting style garners him commendation from his peers watching alongside All Might.
Katsuki again demands that Izuku use his quirk and questions whether Izuku feels he is too good for him now. This irritates Izuku, who expresses that he has always felt Katsuki was better, and that's why he wants to beat him.
Filled with emotion, both fighters rush each other for a final clash. Knowing he cannot defeat Katsuki at close range, Izuku uses his Quirk to smash the ceilings from every building story above him. This smash creates enough debris for Ochaco to use on the floor above. She uses her Quirk to float debris and sends them flying at Tenya, then uses the opening to grab the weapon and secure the victory for Team A.
In disbelief of his loss, Katsuki begins to panic and hyperventilate at the idea of losing again when he is suddenly calmed and consoled by All Might, who tells Katsuki that it does not matter whether he won or lost, but that he takes a look back to reflect on his experience and learn from it. All Might leads Katsuki back to the monitoring room with the rest of the class where they critique the match. Momo Yayarozu comments that Bakugo's attack was far too foolish for the exercise, to which All Might agrees.
Katsuki watches the next match between Team B and Team I. He is visibly stunned by Shoto Todoroki's incredible Quirk. After all the Battle Trial's are completed, Katsuki storms out of the school but is closely followed by Izuku. Once he catches up, Katsuki asks if he will gloat but Izuku reveals that he hasn't been decieving Katsuki about his Quirk.
Izuku goes on to reveal he got his Quirk from someone else and can't yet control it, but Katsuki refuses to believe that. In response, Katsuki admits his failure and inferiority to others even admitting to agreeing with Momo and acknowledges he can't defeat Shoto in a head to head fight. His pride has been damaged, but Katsuki declares that he will never lose again and will follow his dreams to become the best. All Might arrives and tries to console Katsuki again, but this time Katsuki tells him off and promises to surpass the number one hero without his help.
The next day of school, reporters looking for an interview from All Might recognize Katsuki. They ask if he's the victim from the Sludge Villain insident but he only responds by warning them to walk away.
In Class 1-A's homeroom, Mister Aizawa criticizes Katsuki's performance during combat training. He says Katsuki has talent and tells him not to sulk over his defeat. Next, Aizawa asks the class to choose a president. Katsuki tries to get himself elected, but ends up losing out to Izuku. Irritated, Katsuki demands to know who voted for him.
During Hero Basic Training Class, Aizawa informs the class that they will undergo yet another training exercise. However, this time it will be rescue training held at an outside facility. The students suit up in their costumes and head out on a bus to the training area. Katsuki is teased by his classmates on the ride there. Denki Kaminari and Tsuyu Asui both comment on Katsuki's repulsive attitude, outraging him.
When the students arrive at the facility, Rescue Hero Thirteen greets them. Katsuki listens to his explanation on how she built the facility and it is named the Unforeseen Simulation Joint. He goes on to lecture the students about using their powers to save people, but is ultimately interrupted by the arrival of several villains. 
Aizawa orders the class to evacuate with Thirteen, but they're cut off by an ominous villain using his warping Quirk. He introduces himself as Kurogiri of the League of villains. Katsuki and Eijiro hastily attack the villain, but their attacks don't affect his intangible body. Kurogiri counters by using her Quirk to separate the class into the many different simulation zones. Katsuki ends up with Eijiro in the Ruins Zone. 
Together, Katsuki and Eijiro easily defeat the villains trying to ambush them in the Ruins Zone. While discussing what to do next, they disagree on their next course of action. Katsuki wants to defeat Kurogiri and cut off the villains escape route while Eijiro desires to save his classmates.
A villain tries to take Katsuki by surprise, but he swiftly counters and routs the villain. He reassures Eijiro that their peers can handle themselves against the weak criminals. Eijiro is impressed by Katsuki's calm demeanor, but this only angers Katsuki who claims he's always that way. Eijiro continues by stating that perhaps Katsuki is saying to have faith in their peers, and decides to accompany Katsuki's search for Kurogiri 
They arrive at the central plaza just in time to save the day. Kurogiri almost warps Izuku away, but Katsuki swoops in and blasts the villain while yelling for Izuku to get out of his way. Katsuki pins Kurogiri down by his neck armor and explains that he's already discovered the villain's weakness. Kurogiri's body is not fully intangible, he hides his physical form under the black smoke from his Quirk.
By aiming his attack at Kurogiri's neck armor, Katsuki was able to exploit his weakness. He warns the villain not to move, or else he will blow him to pieces. Tomura Shigaraki orders Nomu to free Kurogiri, and Katsuki is not fast enough to react to Nomu. He is saved when All Might takes the brunt of Nomu's attack, but Kurogiri is freed as a result. Katsuki watches the ensuing battle in awe, where All Might uses his incredible power to defeat Nomu.
Katsuki comments on how intense the situation is an decides to remove himself from the rest of the fight. However, Izuku rushes to All MIght's side. Katsuki notices the incredible speed Izuku uses to confront the villains. Izuku and All Might are saved when Tenya returns to the U.S.J. with Pro-Heroes as reinforcements. Katsuki is instructed to leave with the rest of the class and they meet outside the facility. Katsuki continues to wonder about Izuku's Quirk, but is abruptly told by Eijiro to return with the class to school.
Two days after the attack on the U.S.J., Katsuki and his classmates return to school and talk about the attack. Minoru Mineta complains about his fear and Katsuki responds by insulting him and telling him to shut up. After Mister Aizawa returns to class, Katsuki and his peers lectured about the importance of the upcoming U.A. Sports Festival. At the end of the day, Katsuki confronts a mob of students blocking Class 1-A's exit. Katsuki realizes these students must be there to scout their competition for the festival because Class 1-A survived a real villain attack.
He tells the crowd that he is a real future pro for them to move aside, calling them extras. Katsuki is approached by Hitoshi Shinso, who says that although some students may be scouting, he is there to declare war on them. Another student, this time from the other hero course, yells at Katsuki for being arrogant but Katsuki ignores him and walks away. Eijiro says Katsuki can't leave after making everyone hate Class 1-A. Katsuki does so anyway, saying that the people don't matter and the only thing that's important is that he defeats them all.
For the next two weeks before the festival, Bakugo trains at the Replica City District. When the day of the U.A. Sports Festival arrives, Katsuki changes into his P.E. clothes and prepares with his class in their designated waiting room. Like the rest of his peers, Katsuki takes notice when Shoto Todoroki challenges Izuku Midoriya. Katsuki takes exception to this because he feels as if Shoto is declaring war on the wrong person.
Before the festival begins, First Year Chief Referee: Midnight calls Katsuki to the stage to lead the pledge. Instead, he simply announces that he will win the games, angering his fellow competitors and generates boos from the crowd. Midnight announces the preliminaries will be an Obstacle Race four kilometers around the stadium, which immediately begins after the rules are explained. Shoto gets out to an early lead by freezing the stadium's exit, but Katsuki avoids the ice by using his explosions to propel himself past them.
Using his explosions to move through the air, Katsuki flies overtop the villain-bot blockade. He is followed close behind by Hanta Sero and Fumikage Tokoyami. Hanta comments that he expected Katsuki to try and blast through the blockade, and is impressed by Katsuki's strategy. Katsuki reaches the next obstacle soon after: The Fall, a canyon laced with tightropes. Katsuki avoids using the tightropes all together by flying over the canyon completely. After Shoto reaches final leg of the race: the Mine Field and is forced to slow down, Katsuki finally catches up to him.
Katsuki yells at Shoto for declaring war on the wrong rival, and the two engage in combat as they run for first place. Then suddenly, a giant explosion goes off, propelling Izuku past both of them. Although Katsuki and Shoto momentarily catch back up, Izuku uses a second explosion to stop them for just enough time to cross the finish line first. Katsuki crosses the finish line after Shoto, placing him in third. Katsuki is enraged after losing to Izuku again, but he qualifies for the second round: The Cavalry Battle.
While Midnight explains the rules of the Cavalry Battle, she notes that anyone who knocks other teams down will be disqualified, irritating Katsuki. Having placed third in the Obstacle Race, Katsuki is worth two hundred points for the Calvary Battle.
While everyone scrambles to make teams for the second round event, many students from Class 1-A try to convince Katsuki to form a team with them. However, he is unable to recall their names or their Quirk's, making them comment negatively on his ego. Then Eijiro asks to join but Katsuki forgets his name as well and greets him as dumb hair. After correcting him, Eijiro pitches his Quirk's compatibility to Katsuki's. Katsuki says he needs someone with guts and Eijiro replies that they should go after Izuku's ten million points together, exciting Katsuki.
Team Bakugo is formed with Katsuki as the rider and Mina Ashido, Hanta Sero and Eijiro as his horses. After the Cavalry Battle begins, Katsuki flies through the air and tries to attack Team Midoriya, who are flying using a jet pack and Ochaco's Quirk. Katsuki nearly blasts the team, but he's blocked by Fumikage Tokoyami's Dark Shadow Quirk. Unfimilair with Fumikage, Katsuki is frustratedly asks what his dark shadow is. Katsuki falls out of the air, but is caught by Hanta's Tape Quirk.
Soon after, Katsuki's headband is stolen by Neito Monoma from Class 1-B. Neito takes a moment to explain that Class 1-B purposely placed low in the Obstacle Race to scout their Class 1-A Rivals, calling them fools for obsessing for winning over the preliminaries. He continues to taunt Katsuki by recognizing him as the victim from the sludge villain incident. Now absolutely livid, Katsuki explains that his team has a new agenda: to annihilate Team Monoma before they go after Izuku.
Katsuki attacks Neito, but the latter evades and then counters using an explosion of his own. When Katsuki tries to blast him again, Neito uses Eijiro's hardening power to block it. This forces Katsuki to realize that Neito's Quirk is the ability to copy other Quirks. When Katsuki tries to attack again, his team is immobilized by Neito's classmate: Kojiro Bonto. As Team Monoma runs away, Neito takes a moment to taunt Katsuki over his address at the opening ceremony for the festival. This infuriates Katsuki, but his determination to win remains steadfast.
Mina uses her Quirk to free the team and Katsuki uses an explosion to propel himself at Team Monoma. One of their memebers: Kosei Tsuburaba uses his Solid Air Quirk to repel Katsuki, but only for a few moments. Katsuki punches through the air shield and grabs two of the headbands around Neito's neck as he tries to flee, then Hanta recovers Katsuki using his Tape Quirk. Undeterred by his team's elevation into second place, Katsuki orders his team to continue pursuing Neito. Katsuki claims that he will go after Izuku's ten million points after they recover the headband Neito stole from them.
Katsuki strategically uses his teammates Quirk's to close the distance between the two teams. Kosei tries to stop him, but Katsuki blasts through the air shield and takes Neito's last headband. All Might is impressed that Katsuki understands a truth that no one needed to teach him: "there's a difference between those who aim for the top and those who settle, and that difference matters". Mister Aizawa comments that although Class 1-B had a good strategy, they failed to take Katsuki's "overwhelming tenacity" into account. Even after securing more then enough points to advance, Katsuki urges his team to go after the Izuku's team.
With only seconds remaining, Katsuki's team joins the frey already brewing between Team Midoriya and Team Todoroki. Kasuki notices that Team Todoroki has secured the ten million points, and damns Shoto for it. Katsuki tries to go after Shoto, but time runes out. Despite placing second in the event and moving onto the finals, Katsuki is extremely frustrated after failing to be the undeniable champion of the round.
During the lunch break, Katsuki secretly eavesdrops on Shoto's conversation with Izuku in the student entrance corridor. Shoto explains that his father created him to usurp All Might, and he plans to win the festival without using his fathers power. Katsuki leaves after Izuku replies that he will do his best to defeat Shoto.
Midnight reveals that the finals will be a one on one fighting tournament and everyone draws lots for their matchups. Katsuki is set to face Ochaco Uraraka, but he fails to recognize her name and questions who she might be.
Katsuki watches the first match between Izuku and Hitoshi Shinso. He becomes nostalgic when Izuku wins using the same shoulder throw he used during the Battle Trial. Denki reminds him of this, Katsuki tells "Sparky" to shut his mouth.
Seven matches later, Katsuki takes to the ring to face his opponent: Ochaco Uraraka. He warns "pink cheeks" to withdraw from the match because he isn't going to hold anything back. She refuses and starts the engagement by rushing Katsuki. He immediately blows her away with an explosion and repeats that she should've dropped out of the tournament. He blasts her again, only to realize he's exploded only her jacket. She threw it through the smoke as a distraction and nearly gets the drop on Katsuki. Thanks to his incredible reaction time, he's able to blast Ochaco away before she can touch him and use her Quirk to send him out of bounds.
Ochaco continues to rush Katsuki over and over again, and although Katsuki contiues to blast her repeatedly, she continues her assault without resting between attacks. The crowd starts to boo Katsuki for being too rough, but Aizawa calls out the man who starts the uproar. He explains that Katsuki's fierceness is an acknowledgement of his opponent's strength, and he's simply doing everything he can to keep Ochaco at bay so he can come out on top.
As the smoke clears from all the explosions, Ochaco remains undeterred, still standing from Katsuki's barrage. Katsuki keeps his guard up, uneasy that Ochaco "isn't dead yet". This time, rather then dashes at him, Ochaco thanks Katsuki for keeping his focus on her. Confused, Katsuki glances up to see a great amount of debris floating high above them. Ochaco kept low to the ground as she moved so that Katsuki's explosions tore up the floor of the ring, creating weapons for her. Then she kept him focused on her by attacking relentlessly, rendering Katsuki oblivious to the impending meteor shower.
As she releases her Quirk, causing all the debris to fall down towards Katsuki, Ochaco rushes at him to try and capitalize on an opening. Without any other choice, Katsuki unleashes a large, powerful explosion that repels all the debris, horrifying his opponent as she gets blown away as well.
Katsuki figured Ochaco would have some sort of plan since she is friends with Izuku, and quietly states to himself that this was a close call. Katsuki rushes Ochaco, claiming it is time to get serious. She tries to stand up and fight, but ends up collapsing. He keeps his guard up even as she craws towards him, but Ochaco ultimately falls unconscious and Katsuki is declared the winner.
On his way to the student section, Katsuki happens upon Izuku in the hallway and is immediately irritated by his presence. He accuses Izuku of providing Ochaco with her "annoying" strategy, but Izuku denies it and says that if the battle was harder then Katsuki had anticipated, then it is because of Ochaco's own plan and not his. Katsuki eventually makes his way back to the stands with his classmates, who tease him for playing the villain in his fight. He angrily tells them to shup up, and Denki comments in disbelief that Katsuki would aim a powerful explosion at a fragile girl. Katsuki sits down and replies that he most definately would not label Ochaco as frail.
As the match between Izuku and Shoto begins, Eijiro returns from his victory to sit down with his class. Eijiro tells Katsuki that they will fight next, to which Katsuki replies that he kill him. Eijiro laughts it off and then sarcastically says it must be nice that Katsuki and Shoto can use attacks that blast the entire stadium. Hanta adds that they also do not need to pause between attacks. Katsuki calls them morons and explains that just like spriting drains your breath, Quirks can be worn out because they are physical abilities too. Then Katsuki thinks to himself about his own limits and muses over that he designed his costume so that he could fire off stronger blasts then his body normally allows him to.
Continuing to watch the battle between Izuku and Shoto closely, Katsuki notes that Shoto's movements have become sloppy and assumes the reason behind it is because all the frost forming on his body. Katsuki compares Shoto's Quirk to that of a video game's MP meter. When the match ends, Katsuki is taken back by Izuku's defeat.
As the second round proceeds, Katsuki faces Eijiro in his next match. Katsuki and Eijiro trade blows, but Eijiro's hardened body dampens Katsuki's Explosions while Katsuki's cheek is cut open by Eijiro's hardened punch. Katsuki is forced on the defensive because of Eijiro's defensive abilities, but is eventually able to injure Eijiro after landing a few more explosions.
Katsuki realizes that Eijiro's Hardening weakens through continuous strikes and takes advantage of that by barraging him with a series of explosions. Eijiro's defense eventually gives way and he is knocked unconscious by Katsuki's final blast.
In his semi-final matchup, Katsuki duels with Fumikage Tokoyami. He comments that Fumikage's Dark Shadow is annoying and continues to brualize it using his explosions. Fumikage is forced completely on the defensive as Katsuki's attacks continue to get faster, not giving his opponent any room to counter attack.
After striking Dark Shadow with an explosion in mid-air, Fumikage orders it to grab Katsuki, but he evades and jumps behind them. Then Katsuki uses his stun grenade technique to flood the arena with light and pins down Fumikage by exploiting his weakness. Fumikage asks if Katsuki knew his weakness all along, to which Katsuki replies he learned by attacking over and over again. Katsuki admits it was an unfair match up for Fumikage and tells him that he's finished. Fumikage surrenders and Katsuki proceeds to the finals to face Shoto Todoroki.
Katsuki accidently barges into the wrong waiting room and finds Shoto there. He yells at Shoto for being in the waiting room until he realizes that he's actually entered the wrong room. Shoto doesn't pay Katsuki any mind, much to his irrititation. He uses a small explosion to try and intimidate Shoto, saying that he better bring his best to their upcoming bout. Shoto replies that Izuku told him the same thing, and then asks if he was so helpful during their childhood. This greatly annoys Katsuki, who kicks over the table and yells for Shoto to ignore Izuku and his family issues so that he can use his fire during their battle. Katsuki angrily exits the room and states he wants to everyone to know he beat Shoto at full strength. While walking through the hallway Katsuki muses over the thought of bombing the entire stadium in the finals.The U.A. Sports Festival's finale between Katsuki and Shoto begins soon after. Shoto opens the fight with a large scale ice attack. At first it appears that Katsuki is frozen inside the icy prison, but he endures it by blasting through the ice with his explosions. After freeing himself from the frozen prison, Katsuki says Shoto has powerful attacks, but he also has bad aim and needs to try harder. He rushes Shoto, who attempts to touch him with his right side, but Katsuki uses a small explosion in mid-air to avoid being frozen. Katsuki grabs on to Shoto's left side and throws him away. Shoto recovers by creating a wave of ice that he surfs and sends towards his opponent.
Katsuki tries to blast Shoto, but he avoids and grabs onto Katsuki's arm using his left hand. Instead of burning Katsuki, Shoto simply tosses him away. This only annoys Katsuki, who questions if Shoto feels he's unworthy of his flames. He continues, threatening to kill Shoto and berates him for not giving their match his best. Katsuki demands Shoto use his fire so that he can defeat him at his best and prove that beyond a shadow of a doubt that he is the strongest student at the festival.
Shoto mulls over his words until suddenly Izuku starts cheering for him from the crowd. Katsuki notices and comments that Izuku is a stupid nerd before propelling himself in the air. Encouraged by Izuku, Shoto ignites his flames, exciting Katsuki. To counter, Katsuki decides to use his special move: Howitzer Impact. He begins his attack by using small explosions to propel himself in a circualr motion and create a twister that surrounds him. However, just as the two superpowers are about to clash, Shoto extinguishes his flames and exposes himself to Katsuki's large scale explosion.
When the smoke clears, Katsuki realizes Shoto did not actually use his fire and has been blasted outside the ring. Unsatisfied, Katsuki runs over to Shoto even though he's unconscious and furiously demands that he get back up because a victory in this manner is meaningless to him. Midnight uses her Quirk to knock Katsuki out and declares him the victor of the battle and first year champion of the U.A. Sports Festival.
When Katsuki awakens he goes ballistic with fury, still angry with Shoto for basically throwing their match. He has to be restrained and chained to the champions podium during the closing ceremony for the festival. All Might removes the mask on his face before congradulating him on foreshadowing his victory during the opening ceremony. He notices Katsuki's face is scary thanks to his undeniable rage and tries to give him the gold medal. Katsuki refuses and tells All Might to get that "garbage" away from him because he still hasn't proved he's the best. All Might tries to encourage Katsuki to accept the medal even if it's just as a scar. Katsuki refuses, so All Might forces it in his mouth.
After the Sports Festival concludes, Class 1-A returns to their homeroom class, where Aizawa grants them the next two days off. Katsuki is still visually upset with the way he's won. Katsuki remains fuming even until the next day, where he wakes up and noon and angrily brushes his teeth, yelling for his mouth germs to die.
Katsuki returns to class two days after the Sports Festival. Mister Aizawa teaches them about Hero Informatics and reveals the draft results prior to the festival. Katsuki received 3,556 offers from Pro Heroes, second highest in the class behind only Shoto. Denki comments that this is because Pros may have been reluctant to send nominations to a student who needed to be chained up at the end of the festival. Katsuki angrily replies that if a Pro was scared away, than they are just weak.
Midnight joins the class to help them select hero names for their upcoming internships. Initially Katsuki tries to choose King Explosion Murder (爆殺王 Bakusatsu Ō?), but Midnight says it's too violent. While Katsuki re-writes his code name, he notices Izuku chooses Deku as his moniker. Once everyone else is finished presenting Katsuki changes his alias to Lord Explosion Murder (爆殺卿 Bakusatsu Kyō?) and Midnight comments that it's basically the same as before.
At lunch time, Katsuki finds himself irritated while listening to the class discuss Izuku's workout regiment. When first day of the internships arrive, Katsuki receives his costume and boards a train to Best Jeanist's agency.
When Katsuki arrives at Best Jeanist's office in Tokyo, Best Jeanist admits that he isn't very fond of Katsuki because of his attitude despite being talented enough to take on as a sidekick. Katsuki is irritated by the Number 4 Hero's lecture and tries to approach him, forcing the Pro to restrain him using his Quirk. Best Jeanist continues, stating that he will transform Katsuki into an exemplary hero by the end of their time together.
The next day, Best Jeanist scolds Katsuki on the importance of a hero maintaining an elegant appearance. He styles Katsuki's hair similarly to his own, prompting Katsuki regret choosing his agency.
After Stain's defeat is published, Best Jeanist explains that the Hosu City incident is all over the news, but reminds Katsuki and his sidekicks that they must remain calm and collected. While Best Jeanist tells everyone that everything will run smoothly as normal, Katsuki mulls over his poor choice of an internship.
Sometime during the internship, Katsuki goes out on patrol with Best Jeanist. He asks Bakugo the importance of patrolling, to which he answers so that they can find and beat up villains easier. Best Jeanist says this answer is wrong and corrects him. Patrols are to show the public who heroes are and give them peace of mind. Then, a few small children recognize Katsuki from what he believes to be the Sports Festival. However, they actually recall him from the Sludge Villain incident. This angers Katsuki, who yells at the kids and makes them cry. Best Jeanist asks Katsuki to deal with them properly, but Katsuki ends up intimidating them further. .
The internship concludes at the end of the Week and Katsuki returns to U.A. High. His first day back he is immediately met by Eijiro and Hanta hysterically laughing and making fun of his new haircut. Embarrassed, Katsuki lashes out at them in anger and his hair returns to normal. During Basic Hero Training, Katsuki watches the Rescue Training Race and notices Izuku's new abilities are copies of his own movements. Katsuki is greatly irritated that Izuku improved a great deal while he was stuck wasting his time with Best Jeanist.
One week prior to Final Exams, Eijiro notes that Momo is being virtuous in her studies and suggests that he may join her. Katsuki angrily reminds him that he came in third in mid-term grades and asks if Eijiro wants him to beat the lessons into his head. After lunch, Katsuki overhears Denki and Mina talking about how the practical portion of the finals comprises of fighting foe villains. Katsuki believes they're far too excited and yells at them both, telling them they need to learn to control their Quirks. He turns his attention to Izuku and states that the way the latter is using his Quirk now is pissing him off. Ochaco figures that Katsuki is referring to Izuku's movements during the rescue training race. Katsuki claims that he doesn't want an empty victory like the U.A. Sports Festival, and says that their personal grades in the upcoming finals will determine their status. Katsuki also threatens to defeat Shoto as well before he storms out of class. Eijiro notes that Katsuki hasn't been so intense in a while, and Fumikage replies that impatience and hatred have gotten the better of him. As Katsuki walks through the school corridors, Aizawa notes that Katsuki is getting worse.
In the days leading up to final exams, Katsuki helps Eijiro study. After completing the written portion of the exams, Katsuki and his class meet at the training grounds in their costumes for the practical portion. There, Class 1-A meets with the teachers and Principal Nezu explains that the practical has been changed from fighting robotic villains to being paired together and facing off with one of the teachers. Katsuki is shocked to find out that he and Izuku have been paired together against All Might in the tenth and final match.
Nezu goes on to explain that students can either escape or handcuff their teacher to pass the exam within thirty minutes. All Might adds that the teachers will wear high-density weights to give the students a handicap. Katsuki claims that the teachers are underestimating the students and All Might replies that they will see during their battle. Aizawa dismisses the students, and Katsuki shuns Izuku to wait for their battle alone. 
When the time arrives for their match, Katsuki tries to ignore Izuku while walking through the replica city. Izuku pleads with Katsuki to consider escaping rather than fighting All Might. Katsuki refutes him and says that he will beat All Might himself. Izuku replies that it isn't possible, angering Katsuki enough for him to hit Izuku and demand he stops speaking. Izuku says he's trying to communicate so they can pass, but Katsuki replies that Izuku's power isn't needed in this battle. They begin yelling at each other but are interrupted when a shockwave sent by All Might decimates the city street.
Katsuki notices All Might's malicious presence and notes how intimidating it is. Izuku wishes to run, but despite this Katsuki decides to stand his ground. He uses Stun Grenade to blind All Might but the hero resists and grabs Katsuki's face. Katsuki counterattacks with small consecutive explosions that don't appear to harm All Might and he slams Katsuki into the ground. When he recovers Katsuki tries to rush All Might but ends up crashing into a fleeing Izuku. After the recoil Izuku tells Katsuki they need to retreat and Katsuki replies that he will win because that's what heroes do. This prompts Izuku to remember their childhood and how Katsuki admired All Might as a hero because he always won in the end regardless of the situation.
Izuku continues his pleas to no avail and then suddenly All Might pins down Izuku using a guardrail before sending Katsuki flying with a punch powerful enough to make him vomit. All Might approaches Katsuki and says he understands Katsuki's anger is because of Izuku's sudden growth. He continues, saying that Katsuki is stifling his own potential but Katsuki interrupts and says that if he has to work with Izuku, then he'd rather lose. Disappointed with his students reply, All Might prepares to finish him off. Izuku swiftly comes to the rescue and punches Katsuki away, telling him not to say he'd rather lose. Izuku carries Katsuki away down an alleyway until Katsuki makes him stop. He tells Katsuki to at least try working together because saying he'd rather lose is against Katsuki's nature.
Angered, Katsuki blasts the piece of wall next to Izuku's head and says that they can't avoid fighting All Might. Katsuki believes their only chance is to blast him at point blank range with all the firepower they have. When All Might passes by their alleyway, Katsuki makes himself known and blasts All Might from behind. All while struggling to come to terms with his decision to work with Izuku. Once Katsuki gets All Might's attention, he calls for Izuku to appear behind the number one hero, having given him a grenadier bracer beforehand. Izuku pulls the pin from the gauntlet and blasts All Might. He questions how Katsuki has been using such a powerful weapon and Katsuki orders them to run for the escape gate together. 
While fleeing, Katsuki notices that All Might destroyed the entire area from their initial entrance to the escape gate earlier. Izuku comments that All Might isn't chasing them and perhaps got knocked out by the explosion. Katsuki tells him that he's an idiot for believing that and gets taken by surprise when All Might suddenly catches up to them with his blistering speed and breaks both of the grenadier bracers. All Might knees Katsuki into a building and grabs Izuku. Katsuki quickly recovers and rushes All Might again, only for him to slam Izuku into him and subsequently pin them both down. While immobilized, Katsuki mulla over All Might's overwhelming power and admits he is the worlds greatest hero.
All Might dissects their earlier plan and states that the fight is over because he's destroyed the grenadier bracers. Katsuki demands he stops talking and blasts All Might with a super explosion similar to the one he used against Ochaco in their Sports Festival fight. Then he grabs Izuku and warns him he's going flying. He throws Izuku towards the escape gate only for All Might to smash him into a nearby bus. Katsuki rushes over to distract All Might and admits to himself that it was foolish to believe he could best All Might without taking any risks, and uses a second super explosion against him. Izuku moves slowly towards the gate and Katsuki yells for him to hurry. Katsuki continues to blast All Might with super explosions so that Izuku can make for the escape point which would force All Might to stop him. All Might does just that, giving Katsuki the opening they were looking for. However, All Might avoids Katsuki's attack and slams him into the ground. Falling out of consciousness, Katsuki bites All Might's hand and says he refuses to believe that he can't win even if he's up against All Might.
Surprisingly, Izuku does not escape; instead, he rushes back to help Katsuki. Izuku smiles and punches All Might in the face, asking his mentor to move aside. While All Might is suffering from slight recoil, Izuku grabs Katsuki's unconscious body and gets through the escape gate.Katsuki and Izuku pass the exam and are taken to Recovery Girl's office to receive treatment. Recovery Girls scolds All Might for not restraining himself during the fight. Recovery Girl says that Katsuki likely won't wake up for a while and they should both rest with her. All Might muses over Katsuki's ability to smile in the face of adversity and claims that he will become much stronger in the future. 
Once final exams conclude, Katsuki learns that he passed both portions of the final exams and will attend training camp during the summer. After class, Katsuki's peers decide to go shopping to buy what they need for the camp. Eijiro asks Katsuki to join them, but he refuses. 
The next day at U.A., Shota informs Class 1-A that the destination for their lodge trip has been changed and the new destination will only be announced on the day of the event. During class, Katsuki criticizes Izuku for not trying to attack the villain holding him hostage. The first semester has come to a close and summer break has begun.
On the day of the event, Class 1-A boards a bus that will take them to the forest lodge destination. An hour later, Class 1-A’s bus stops for a restroom break. However, Class 1-A notes that Class 1-B isn’t at the rest stop. Suddenly, two females wearing cat-like costumes and a small boy appear; the females excitedly introduce themselves as the professional Hero Team, The Pussycats. Mandalei explains to Class 1-A that they will be staying at the base of a mountain which is a part of their domain; they have three hours to reach the base of the mountain using their Quirks as they please and those who don’t arrive there by 12:30 pm won’t be served lunch. Soon, Class 1-A realize that they have already arrived at their destination and their training camp has already begun with the Pussycats being their supervisors. Some of Class 1-A try to leave, but Pixiebob uses her Quirk to create a landslide of dirt that causes Class 1-A to fall into a forest called Forest of Magic Beasts, which they must traverse to reach their destination. Suddenly, Class 1-A are confronted by a beast; Kouji tries using his Quirk to control the beast but it does not work due to the beast being made out of dirt. Katsuki along with Shoto, Tenya and Izuku mobilize and use their Quirks to destroy the dirt beast.
After Izuku, Tenya, Shoto, and Katsuki destroy the dirt beast, Class 1-A begins traversing the Forest of Magic Beasts. However, the journey through the forest to the Cabin takes around about 8 hours. Class 1-A arrive at the facility, battered and tired. It is now 5:20 pm in the evening. Pixiebob admits that she thought they would take longer to get to the facility; she praises Class 1-A for figuring out her Earth Beasts quickly and easily. Pixiebob then commends Izuku, Tenya, Shoto, and Katsuki for taking quick action against one of her Earth Beasts and concludes that they have experienced action against villains. After Kouta punches Izuku in his crotch and harshly replies to Tenya, Katsuki comments that Kota thinks he is an adult; Shoto replies that Kota reminds him of someone who also acts like an adult (referring to Katsuki himself). Katsuki tells Shoto that he does not keep his emotions bottled up like someone he knows (referring to Shoto) while Shoto replies that he was joking.
Class 1-A fetch their luggage and put it in their rooms, Class 1-A head to the dining hall and have dinner; they enjoy the delicious food that the Pussycats provide them. After finishing dinner, Class 1-A go to the hot springs.
The next day at 5:30 AM, Class 1-A are outside the training camp cabin. Shota greets his students and tells them that they will undergo reinforcement training to strengthen and upgrade their Quirks which will also allow Class 1-A to obtain their temporary licenses. Shota tells Katsuki to perform the pitch from the Quirk Apprehension Test. Katsuki throws his pitch; however, Katsuki’s pitch records at 709.6 m, which is a minor increase from his last pitch. Some of Class 1-A are surprised with the lack of difference with Katsuki’s new pitch as they were expecting it to be immensely higher. Shota explains that while Class 1-A has grown emotionally and technically, their Quirks have not which is why they are having the training camp to upgrade their Quirks.
Katsuki trains along with the rest of his class. Later that day at 4:00 PM, Pixiebob and Ragdoll provide Class 1-A food materials and tell them that they must make their own food from now on. Tenya sees this as survival skill training and motivates his class to start making curry. Class 1-A begin making their own curry and after doing so, eat it for dinner. On the third day, Katsuki continues his training along with his class and Class 1-B.
Later that night after dinner, Katsuki is paired with Shoto for the test of courage. A few minutes after entering the forest, Yui tries scaring Katsuki and Shoto, although to no avail. Suddenly, the League of Villain's Vanguard Action Squad attacks. Shoto, who is carrying an injured Kosei Tsuburaba, and Katsuki run through the forest. Seeing that the situation is chaotic, Shoto decides that they should head back to the facility to regroup. While running to the facility, Shoto and Katsuki encounter Moonfish; Katsuki asks Shoto who is supposed to be ahead of them, to which Shoto answers Fumikage and Mezo. The villain is admiring something on the ground; a severed arm. However, the villain realizes he has work to do and cannot afford to be distracted by the severed arm; the restrained villain turns his attention to Katsuki and Shoto.
Shoto engages in combat with Moonfish, using his ice to block the villain's teeth enlarging Quirk. Moonfish proves to be highly skilled, being able to break through Shoto's ice and nearly hit Katsuki with one of his teeth, only to be intercepted by Shoto's ice. Shoto warns Katsuki to not use his Explosion Quirk due to the fear of igniting the poisonous gas and causing more chaos, much to Katsuki’s annoyance. Moon Fish continues breaking through Shoto's ice defenses with his teeth enlarging Quirk while also using his teeth to maneuver himself around.
Shoto and Katsuki continue their battle with Moonfish; Shoto is unable to fight properly due to carrying Kosei. The Shoto tries his best to keep Moonfish at bay by blocking his path with ice. Katsuki becomes furious that he is unable to fight back, thinking that firing a huge explosion should stop Moonfish, but Shoto warns Katsuki that the huge explosion will limit their visibility and give the villain more attacking opportunities. When Mezo and Izuku arrive to Katsuki and Shoto 's location, Mezo asks one of them to make light. Before he can explain further, Moonfish senses Mezo and Izuku's presence and sends one of his teeth to attack them. Suddenly, the rampaging Dark Shadow appears and uses its enormous claw to crush Moonfish, destroying Moonfish's teeth. Shoto and Katsuki are surprised at what transpired.
After the rampaging Dark Shadow effortlessly defeats Moonfish, Katsuki and Shoto manage to get close to Fumikage and use their Quirks, which calms down Dark Shadow; Dark Shadow reduces in size and retracts back into Fumikage, allowing Fumikage to return to normal. Katsuki once again tells Fumikage that their Quirks have a bad chemistry; Fumikage thanks Katsuki for saving him. Izuku tells Fumikage that their top priority is to protect Katsuki, who is the target of the villains. Izuku decides that they should escort Katsuki back to the facility and take a shortcut through the forest to do so; Izuku thinks that with the power of Mezo's scouting capabilities, Shoto's powerful Quirk and the unrivaled power of Fumikage's Dark Shadow, escorting Katsuki will be a cinch. However, Katsuki is angry that he needs protecting and refuses their help. The Bakugo Escort Squad (consisting of Mezo, Shoto, Izuku, and Fumikage) begin escorting a begrudging Katsuki back to the facility.
The Bakugo Escort Team travel to the facility and come across Ochaco and Tsuyu. After seeing that Ochaco and Tsuyu are alright, Izuku asks them to join the escort. However, Ochaco and Tsuyu wonder why Katsuki is not with them. Mezo, Shoto, and Izuku turn around only to find that Fumikage and Katsuki are missing.
Suddenly, Mr. Compress appears on a tree branch and reveals that he used his "magic" to take Katsuki by turning him into a marble. The villain states that the Heroes do not deserve someone of Katsuki's caliber and notes that Katsuki will shine even brighter on the villains' side. Izuku demands that he give Katsuki back. Izuku, Mezo, and Shoto chase after Mr. Compress in order to rescue Fumikage and Katsuki.
At the Vanguard Action Squad's rendezvous point, thanks to Yuga firing his Navel Laser at Mr. Compress, Katsuki's compressed form is released from Mr. Compress's grasp. Shoto tries grabbing Katsuki, only for Dabi to snatch Katsuki away. Dabi orders Mr. Compress to deactivate his Quirk, which he does. Katsuki is freed from his marbled prison but is grabbed on the shoulder by Dabi to prevent him from escaping. Izuku desperately tries rescuing Katsuki but to no avail. Before warping away with Dabi, Katsuki tells Izuku to stay back. The warping completes and the captured Katsuki teleports away along with the Vanguard Action Squad.
Inside the League of Villains' hideout, Katsuki is strapped and restrained on a chair being surrounded by members of the Vanguard Action Squad, Kurogiri and Tomura. Tomura asks Katsuki to become his ally, but Katsuki vehemently tells him to drop the small talk and die.
After Katsuki and the League of Villains watch a video clip of U.A.'s public apology, Tomura understands why society is blaming U.A. for their failure and that is because the current Hero society is not just. Spinner agrees that the current Hero society is not just since the modern Heroes are only doing their job for compensation and not out of selflessness. Tomura explains that the League of Villains are fighting for a just society and intends to win this battle. Tomura orders Dabi to remove Katsuki's restrains, although Dabi is unsure since Katsuki might attack; Tomura wants to treat Katsuki as an equal and is aware that Katsuki knows he has no possibility of winning. Dabi has Twice remove the restrains. As Twice removes the restrains, Mr Compress apologizes to Katsuki for forcibly kidnapping him and explains that the League of Villains are not just a group of hoodlums perpetuating crimes nor did they casually abduct him; he goes on by saying that everyone in the League of Villains is shackled by the current society and hopes that Katsuki understands their discrimination.
Katsuki's restraints are removed. As Tomura approaches Katsuki, Katsuki attacks Tomura with his Explosions. Katsuki tells the League of Villains that it is pointless to try and make him change his mind as he has already been won over by the way All Might looks when he wins. Katsuki says that from the beginning he has dreamed of becoming a Hero and surpassing All Might and nothing they say will change that.
After hearing Shota state that Katsuki desires to be a Hero, Katsuki tells his captors that U.A. are correct about him desiring to be a Hero. Katsuki taunts the Vanguard Action Squad and Tomura, telling them that his combat authorizations have not been revoked. However, Dabi, Himiko, Kenji and Mr. Compress are not intimidated; they wonder about Katsuki's mental state and conclude that he has messed up by going against them. After picking up his hand, Tomura decides that he must use force on Katsuki and asks his teacher, Sensei, to help him do so.
Tomura orders Kurogiri and Mr. Compress to knock out Katsuki. Katsuki continues insulting the League of Villains while thinking of a way to cause a distraction that will allow him to make a run for the door behind him.Suddenly, All Might breaks in with Kamui Wood swinging in and restrains the League of Villains with his Lacquered Chains Prison. All Might checks on Katsuki and compliments him for not being afraid, much to Katsuki's chagrin.
As Gran Torino and All Might attempt to get information about Sensei from Tomura, mysterious black liquid appears with dozens of Noumus appearing out from the phenomenon. All Might grabs hold of Katsuki. Suddenly, Katsuki is engulfed by the black liquid and dissolves into it, much to All Might's fury.
Katsuki is teleported by the mysterious black liquid to Sensei's location which is near the ruins of the League of Villains' warehouse. Sensei apologizes to Katsuki as Tomura, Kurogiri and the Vanguard Action Squad finish materializing from the black liquid's teleportation.
All Might appears and clashes with Sensei. After All Might is blasted away, Katsuki becomes concerned, but Sensei tells Katsuki not to fret since his blast wave attack isn’t strong enough to kill him. Sensei uses a Quirk to forcefully activate Kurogiri's Warp Gate Quirk, causing a portal to appear and instructs the League of Villains to leave with Katsuki. However, Katsuki is not willing to give himself up so easily and prepares to battle the League of Villains. Katsuki fends off Himiko, Twice and Mr. Compress with his Explosions; All Might tries to help Katsuki only for Sensei to intervene.
During the battle, Izuku, Tenya, and Eijiro appear in the air from above. Katsuki sees the trio while Eijiro yells at Katsuki to take his hand. Tomura tries to take Katsuki, but Katsuki uses his Explosion to launch himself towards Izuku, Tenya, and Eijiro. Katsuki grabs Eijiro's hand and smiles.
Kenji and Spinner launch Mr. Compress into the air, but Mt. Lady intercepts him, allowing Izuku, Eijiro, Tenya, and the rescued Katsuki to get away. The boys land on the ground far from the battlefield and begin escaping.
Katsuki manages to escape to the front of the train station. Eijiro and Katsuki converse, with Katsuki stating that he was not rescued and that he only escaped with them so that he would not get in All Might's way. Katsuki watches the broadcast of the battle between All Might and All For One and becomes surprised upon seeing All Might's true form. Many civilians encourage All Might to win, with Izuku and Katsuki also encouraging him.
After the battle, Izuku and his group meet up with Shoto and Momo. They take Katsuki to a Police Station for his safety.
The Police Force take Katsuki back home. Shota and All Might visit the home of Katsuki Bakugo. Inside, Mitsuki Bakugo agrees to the U.A. students' relocation, being more than happy to send her son away. Katsuki and his mother begin arguing with each other while Masaru Bakugo tries to calm them down. After calming down, Mitsuki notes that Katsuki's rashness, along with his gifted abilities, has resulted in him being pampered and getting shallow praise for what he has. However, Mitsuki is happy that Shota sees her son for who he is instead of his gifted abilities. She once again agrees to leave Katsuki in U.A.'s care since her son returned home safe and sound thanks to the Pro Heroes, and asks Shota to make her son into a fine Hero.
As Shota and All Might leave the Bakugo household, Katsuki asks All Might what Izuku is to him. Unable to tell Katsuki the truth, All Might informs Katsuki that Izuku is a student to him who has great potential just like Katsuki. Satisfied to a degree with All Might's answer, Katsuki thanks All Might for everything and goes back inside his house.
Katsuki fails the Hero License Exam.